I think its not possible to have multiple versions of same application for different countries. E.g: If version 1 is released to whole world, now version 1.1 is released for the same app (You are updating and not adding another app) and selected only US then Result - US will have version 1.1 and rest of world would not have your app.
To satisfy your case, I would suggest to keep different applications based on the countries you want to release in. It would be tedious to maintain same code base for different countries but I think it may solve your problem.